Fire-resistant functional fluids



United States Patent U.S. Cl. 25249.9 12 Claims ABSTRACT OF THEDISCLOSURE Homogeneous fire-resistant, low cost, functional fluids aredisclosed which are composed of 40 to 50% highly chlorinatedhydrocarbons containing at least 48% by weight chlorine, 20 to 30%petroleum-base oil, 5 to 20% liquid triaryl phosphate, 8 to 35% trialkylphosphate which serves as a mutual solvent for the other ingredients andstabilizing amounts of a triorganic phosphite and an epoxy plasticizer.

CROSS REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of United States patent application No. 601,335,filed Dec. 13, 1966, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention Fire-resistantfunctional fluids.

Description of the prior art Many fire-resistant functional fluids areknown. Desirably a functional fluid should have viscositycharacteristics such that it may be used over a wide temperature range;it must not adversely affect the materials of construction of the systemin which it is used; it must possess adequate lubricity and mechanicalstability in order that it may be used in valves, pumps, self-lubricatedpumps and other components of hydraulic power systems; and it should notbe abnormally toxic or otherwise harmful to personnel who come incontact with it.

Suitable fire-resistant hydraulic fluids and lubricants consistingessentially of a mixture of 2080% triaryl phosphate, 80-20% chlorinatedbiphenyl, and 02-10% polyalkyl methacrylate as a viscosity indeximprover are disclosed in United States Patent No. 3,136,726 to D. H.Moreton. Fluids composed of a mixture of primarily triaryl and trialkylphosphates, and minor proportions of a flame-proofing agent and mineraloil are reported in United States Patent No. 2,549,270, issued toWatson, July 19, 1948. These patented fluids are expensive, because theycontain major proportions of expensive ingredients and very little ofthe cheap mineral oil.

Petroleum-base oils, though good lubricants and economically desirable,are not used in high proportions in fire-resistant functional fluidsbecause of their flammability. Chlorinated hydrocarbons are good flameretardants for petroleum-base oils. The higher the combined chlorinecontent is, the more effective the chlorinated hydrocarbons are as flameretardants. However, the more highly chlorinated hydrocarbons, thosecontaining at least 48% combined chlorine, are not compatible Withmixtures of triaryl phosphates and petroleum-base oils.

Triaryl and trialkyl phosphates are Widely used in fire-resistantfunctional fluids to provide flame resistance and lubricity. Triarylphosphates are preferred to trialkyl phosphates in functional fluids foranti-Wear properties because they cost less than trialkyl phosphates.

3,496,107 Patented Feb. 17, 1970 ice SUMMARY OF THE INVENTION We havenow discovered that inexpensive homogeneous fire-resistant functionalfluids can be prepared which contain major amounts of the inexpensivehighly chlorinated liquid hydrocarbons and petroleum-base oils, togetherwith minor amounts of triaryl phosphates, by including in the fluid aminor portion of a trialkyl phosphate as a mutual solvent for the otheringredients, and a heat stabilizing amount of a mixture of a triorganicphosphite and an epoxy plasticizer. Fluids containing (a) 35 to 50 partsby weight of a highly chlorinated liquid hydrocarbon, (b) 20 to 30 partsby weight of a petroleumbase oil, (c) 5 to 20 parts by weight of atriaryl phosphate, and (d) 8 to 40% by weight of a trialkyl phosphatebased on the total weight of the other ingredients are homogeneous,compatible, fire-resistant functional fluids. The stabilizing phosphiteis added to the functional fluids in an amount of about 0.1 to 1 part byweight per parts by weight of fluid composed of components (a) (b) (c)and (d). The stabilizing epoxy plasticizer is added to the functionalfluids in an amount of about 0.5 to about 2 parts by weight per 100parts by weight of fluid composed of components (a) (b) (c) and (d).Surprisingly, the mixed stabilizers have a stabilizing effect greaterthan that due to the additive effect of the stabilizers.

DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENTS Triarylphosphates suitable for the purposes of this invention are thosephosphates containing 3 hydrocarbon radicals, Where the aromatic nucleusmay contain 0 to 3 alkyl substituents, and the alkyl 'substituents maycontain one to three carbon atoms. These triaryl phosphates particularlyinclude tricresyl phosphate, cresyl-diphenyl phosphate, xylyl-diphenylphosphate, phenyl-dixylyl phosphate, trixylyl phosphate, isopropylphenyldiphenyl phosphate, diisopropylphenyl monophenyl phosphate, trisisopropylphenyl phosphate and mixtures thereof, and liquid mixtures oftriphenyl phosphate, and tricresyl phosphate, etc. The aromaticphosphate esters particularly suitable for the purpose of this inventionmay be represented by the formula:

Where R is selected from the group consisting of phenyl, cresyl andxylyl radicals. Trixylyl phosphate was found to be slightly morecompatible with the other ingredients of these functional fluids thanthe other triaryl phosphates listed above, and is therefore the slightlypreferred aryl phosphate for use in this invention.

The chlorinated hydrocarbons useful in this invention may be any of thecommercially available highly chlorinated paraffins or chlorinatedbiphenyls. The chlorinated hydrocarbon should be liquid and containenough chlorine to impart flame resistance to the formulation. Compoundscontaining at least 48% by weight of combined chlorine are desirable fortheir flame-resistant properties.

The chlorinated hydrocarbons generally have poor heat stability, butthis may be overcome by incorporation of any of a sizeable array of heatstabilizers, The type of heat stabilizers normally used in polyvinylchloride compositions consisting of metal-organic compounds containingbarium, cadmium, zinc, tin, lead, epoxy compounds and organic phosphitesmay be used. Combinations of organo-phosphites and epoxidized oils werefound to be the preferred heat stabilizers for these functional fluids.

The most preferred stabilizer found is a combination of phenyl didecylphosphite and epoxidized linseed oil containing 9.5% oxirane oxygen.

The petroleum-based oils suitable for the purposes of this invention aremineral oils with a Saybolt Universial Viscosity (ASTM Saybolt MethodD-88) in the range of 32-200 SUS at 100 F. and petroleum-base hydraulicoil with a Saybolt Universal Viscosity in. the range of about 140-400SUS at 100 F. The apparently wide viscosity ranges provide finalformulations which meet the different viscosity requirements of varioushydraulic pumps, fluid motors, and other components of hydraulic powersystems.

The trialkyl phosphate useful for inclusion in the present compositionsare those in which the alkyl radical has from 4-12 carbon atoms each andinclude the following: tributyl phosphates, triamyl phosphates, trihexylphosphates, triheptyl phosphates, trioctyl phosphates, trinonylphosphates, tridecyl phosphates, tridodecyl phosphates and particularlybranched homologs such as tris(2-ethylhexyl) phosphate,tris(2-ethylbutyl) phosphate and tris (3,5,5-trimethylhexyl) phosphate,and the like.

Heat stabilizing triorganic phosphites useful in practicing thisinvention include trialkyl phosphites, triaryl phosphites, alkyl-diarylphosphites, tri(alkylatedaryl) phosphites and mixtures of thesephosphites, The organophospite is added in the amount of about 0.1 toabout 1, and preferably about 0.4 to 0.6, part by weight per 100 partsby weight of fluid containing major amounts of the highly chlorinatedliquid hydrocarbon, petroleum-based oil, triaryl phosphate and trialkylphosphate. Suitable phosphites include triphenyl phosphite,phenyl-didecyl phosphite, trioctyl phosphite and the like.

Heat stabilizing epoxy plasticizers, of the type used in stabilizingpoly(vinyl chloride) compositions, useful in practicing this inventioninclude epoxidized oils such as epoxidized soybean oil and epoxidizedlinseed oil, and epoxidized esters such as butyl epoxy tallate, octylepoxy tallate, butyl epoxy stearate, and the like. The epoxy compoundsare added in the amount of about 0.5 to about preferably about 1 toabout 1.5 parts by weight per 100 parts by weight of functional fluidcomposed principally of a highly chlorinated hydrocarbon, petroleum-baseoil and trialkyl phosphate, Epoxidized compounds with high oxiraneoxygen contents are preferred to epoxy compounds with low oxirane oxygencontents.

The novel functional fluids of this invention can be compounded togetherwith conventional functional fluid additives such as heat stabilizers,anti-oxidants, rust preventatives, viscosity index improvers,detergent-dispersion additives and the like.

The following typical examples of formulations pre' pared in accordancewith this invention are given by way of illustration and not bylimitation. The examples were all prepared by simply stirring theingredients listed in each example together. All parts and percentagesare by weight.

EXAMPLE 1 Parts by weight Chlorinated paraffin (50% chlorine) 49Petroleum oil 29 Trixylyl phosphate 13 Tris(2-ethylhexyl) phosphate 8.4Epoxidizedlinseed oil (9.5% oxirane oxygen) 0.6 Triphenyl phosphite 0.25

peated substituting chlorinated biphenyl containing 50% chlorine for thechlorinated parafiin and similar results were obtained.

4 EXAMPLE 2 Parts by weight Chlorinated paraflin (50% chlorine) 49Petroleum oil 29 Trixylyl phosphate l3 Tris(2-ethylhexyl) phosphate 8.4Epoxidized linseed oil (9.5% oxirane oxygen) 0.6

This sample is a homogeneous solution with good lubricity, mechanicalstability and low toxicity. This sample turned significantly darker thanExample 1 after 60 minutes in a 400 F. heat test. The petroleum-base oilof Example 1 was used in this example. This example was repeatedsubstituting chlorinated biphenyl described in Example 1 for thechlorinated paraffin and similar results were obtained.

EXAMPLE 3 Parts by weight Chlorinated paraflin (50% chlorine) 49Petroleum oil 29 Trixylyl phosphate l3 Tributyl phosphate 9 Epoxidizedlinseed oil (9.5 oxirane oxygen) 0.6 Triphenyl phosphite 0.25

This sample possesses good lubricity, mechanical stability and is notabnormally toxic or hamful. The sample showed only slight discolorationafter 60 minutes in a 400 F. heat test. The petroleum oil of Example 1was used in this example. This example was repeated substitutingchlorinated biphenyl containing 50% chlorine This sample possesses goodlubricity, mechanical stability and is not abnormally toxic or harmful.The sample showed only slight discoloration after 60 minutes in a 400 F.heat test. The mineral oil used in this example had a viscosity at F. of-190 SUS and a specific gravity at 15.6 C. of 0.820 to 0.880. Thisexample was repeated substituting chlorinated biphenyl (50% chlorine)for the chlorinated paraffin with similar results.

EXAMPLE 5 Parts by weight Chlorinated paraffin (50% chlorine) 49 Mineraloil 29 Trixylyl phosphate 13 Tributyl phosphate 9 Epoxidized linseed oil0.6 Triphenyl phosphite 0.25

results.

EXAMPLE 6 v I Parts by weight Chlorinated paraffin (50% chlorine) 40Mineral oil 29 Trixylyl phosphate 20 Tris(2-ethylhexyl) phosphate 11Epoxized linseed oil 0.6

Triphenyl phosphite 0.25

This sample possesses good lubricity, mechanical stability and is notabnormally toxic or harmful. The sample that the stabilizing etfect ofthe epoxidized linseed oil showed only slight discoloration and a veryslight iuand triphenyl phosphite is greater than that due to the creasein acidity after 60 minutes in a 400 F. heat test. additive eifect ofthese two stabilizers.

The mineral oil used in this example had a viscosity at 100 F. of180-190 SUS and a specific gravity at 155 EXAMPLE 9 C. of 0.820 to0.880. This example was repeated substituting chlorinated biphenyl (50%chlorine) for the chlorinated paraflin with similar results.

A series of fire-resistant functional fluids were prepared to evaluatethe effectiveness of typical epoxy compounds and organo phosphites asheat stabilizers in fire resistant EXAMPLE 7 functional fluids. Thefollowing test composition was Parts by weight used in this series oftests:

Chlorinated parafiin (50% chlorine) 40 Parts by weight Mineral oil 20inated paraffin (50% chlorine) 49 Trixylyl phosphate 30 pefl'oleuln Oil29 Tris(2-ethylhexyl) phosphate l0 f y y P phate 13 Epoxized linseed oil0.6 Q- Y EXYI) phOSphate 9 Triphenyl phosphite 0.25

All the samples in the phosphite tests contained This sample possessesgood lubricity, mechanical stabil- 0.6 part by weight of expoxidizedlinseed oil per 100 ity and is not abnormally toxic or harmful. Thesample parts of the test composition and the phosphite and phosshowedonly slight discoloration and a very slight increase phite amount werevaried as indicated in Table III. All in acidity after 60 minutes in a400 F. heat test. The the samples in the epoxy tests contained 0.25 partby mineral oil used in this example had a viscosity at 100 w ight oftriphenyl phosphite per 100 parts by weight F. of 180-190 SUS and aspecific gravity at 15.6 C. of of the test composition and the epoxyplasticizers and 0.820 to 0.880. This example was repeated substitutinge oxy plasticizer amount were varied in the test comchlorinated biphenyl(50% chlorine) for the chlorinated position as indicated in Table IV.paraffin with similar results. Fifty gram samples of the testcompositions with the various heat stabilizer compositions shown inTable III EXAMPLE 8 were heated at 400 F. in an oven and observed for Aseries of functional fluids were prepared and evalucolor changes atintervals of 10, 20, 30, 45 and 60 minutes ated to determine theeffectiveness of various epoxy and d 50 gram samples f t composition ithh phosphite heat stabilizers in functional fluids. The comvarious heatstabilizers shown in Table IV were also position details of the fluidsare set forth in Table I and heated at 400 F in an oven, but observedfor color the results of a heat test are listed in Table II. change atintervals of 15, 30, and 60 minutes.

TABLE I a b c d e f Chlorinated parafiin chlorine) 49 49 49 49 49 49Petroleum oil 29 29 29 29 29 29 Trixylyl phosphate 13 13 13 13 13 13Tris(2-ethylhexyl) phosphate 8.4 8.4 8.4 8.4 8.4 8.4 Epoxidized linseedoil (9.5% oxirane oxygen) 0. 6 0.6 0.3 Triphenyl phosphite 0.25 0.25 0.60.3

Fifty gram samples of the functional fluids as shown L above were heatedat 400 F. and observed at intervals TAB E In EFFECT OF PHOSPHITES ONHEATSTABILITY of 20, 30, 40, 50 and minutes. The samples were re- PageMinutes at400 F.

moved from the oven after each time interval and ar- 50 10 20 3o 45 60ranged according to color with number 1 having the a Triphenyl 0 1 9 9 77 7 lightest color and number 6 having the darkest color. Tri 11 niIIjjIjfI ,2 5 4 5 4 c. Triphenyl 0.5 3 2 2 2 The initial color of thetest fluids was amber. After 20 Phenymidecyl 0.1 7 6 8 8 minutes, samplea was only slightly darker than the c. Phenyl-didecyL 2 a 4 5 original,b was only very slightly darker, and the remain- No change g g 3 ingfour samples had little or no observable color change. 6 8 6 6 Obviouscolor ditferences began to show after 30 minutes. 5 3 3 o 10 10 10 Thearrangement of the samples for each time interval 15 recorded in TableII.

TABLE II 30 min. 40 min. 50 min. 60 min.

6 (v. dark brown)-.- 6 (black) 6 (black). 4... 4.... 3 (brown). 5...5..-... 5 (v. dk. brown). 2 2 1(dk.amber). 3 3. .1 4 (dark brown).(slightly darker than original) 1 (slight darkening) 1 (slightdarkening). 2 (light brown).

The above data indicate that sample d is much better The samples wereremoved from the oven after each than either b or c and sample 1 is muchmore resistant time interval and arranged according to color. The datato color change than b or e. The fact that f is much more above indicatethe rank of the samples with respect to resistant to color change thaneither [2 or e clearly shows color, #1 being lightest and #10 darkest.

Sample f was best in all casesinitially amber and turning to a darkamber in 60 minutes.

Sample i was worst in all cases-initially amber and turning dark brown,nearly black, in 60 minutes.

TABLE IV.EFFEOT OF EPOXIES ON HEAT STABILITY Minutes at 400 F.

weight 15 30 45 60 k. Epoxy linseed 1 0. 3 10 11 9 l. Epoxy linseed. 0.6 3' 4 5 m. Epoxy linseed 1. 1 1 1 n. Epoxy soya 0. 3 12 12 10 o. Epoxysoya 0. 6 4 6 6 p. Epoxy soya 1.0 2 2 2 q. Octyl epoxy tallate 0. 3 N 0change 9 o 12 r. Octyl epoxy tallate. 0. 6 8 8 8 s. Ootyl epoxy tallate1.0 6 4 t. Butyl epoxy stearatc 0. 3 11 it u. Butyl epoxy stearate" 0. i7 7 7 v. Butyl epoxy stearabe 1. 0 5 3 3 w. Control, no epoxy 13 13 13 4Epoxidized butyl oleate, 3.9 oxirane oxygen (butyl epoxy steal-ate) Thesamples were removed from the oven after each time interval and arrangedaccording to color.

The data above indicate the rank of the samples with respect to color,#1 being lightest and #13 darkest.

Sample m was consistently best, initially amber and turning to a darkeramber color in 60 minutes.

Sample w was consistently worst, initially amber and turning dark brownto black in 60 minutes.

The test results in Tables III and IV show that greater stability wasobtained with higher levels of stabilizer in both cases. Expoxidizedsoybean oil and epoxidized linseed oil were clearly the best heatstabilizers. The mixed aryl-dialkyl phosphite was superior to the othertwo phosphites.

As will be apparent to those skilled in. the art, numerous modificationsand variations of the invention illustrated above may be made withoutdeparting from the spirit of the invention.

What is claimed is:

1. A liquid fire-resistant functional fluid composition which comprises:(a) 60 to 80% of a mixture of liquid chlorinated hydrocarbons andpetroleum oils, the petroleum oil comprising to of the totalcomposition; (b) 20 to of a mixture of liquid triaryl phosphate andtrialkyl phosphate, the triaryl phosphate comprising at least 5% of thetotal composition, and the trialkyl phosphate comprising at least 8% ofthe total composition; the liquid chlorinated hydrocarbon being selectedfrom the group consisting of chlorinated parafiins containing at leastabout 48% by weight chlorine and chlorinated biphenyl containing atleast about 48% combined chlorine; the petroleum oil being selected fromthe group consisting of mineral oils having a viscosity of about 30 to200 SUS and petroleum base hydraulic oils having a viscosity of about140 to 400 SUS; the liquid triaryl phosphate being selected from thegroup consisting of triaryl phosphates represented by the formula whereR is selected from the group consisting of phenyl, cresyl, and xylylradicals and the liquid mixtures of these triaryl phopshates; and thetrialkyl phosphate being selected from the group consisting of trialkyllphosphates in which each alkyl radical has from 4 to 12 carbon atoms;(0) 0.1 to 1 part by weight, per 100 parts by weight of the total of (a)and (b), phite; and (d) 0.5 to 2 parts by weight per 100 parts by weightof the total of (a) and (b) of an epoxy plasticizer.

2. A fire-resistant functional fluid according to claim 1 of atriorganic phos- 7 wherein the chlorinated paraffin has a molecularweight I Ingredients: Parts by weight Chlorinated paraffin chlorine) 49Petroleum oil 29 Trixylyl phosphate 13 Tris(2-ethylhexyl)phosphate 8.4=Epoxidized linseed oil (9.5 oxirane oxygen) 0.6 Triphenyl phosphite0.25

8. A fire-resistant functional fluid according to claim 1 consisting ofthe following ingredients:

Ingredients: Parts by weight Chlorinated paraffin (50% chlorine) 49Petroleum oil 2-9 Trixylyl phosphate 13 Tributyl phosphate 9 Epoxidizedlinseed oil (9.5 oxirane oxygen) 0.6 Triphenyl phosphite 0.25

'9. A fire-resistant functional fluid according to claim 1 consisting ofthe following ingredients:

Ingredients: Parts by weight Chlorinated paraffin (50% chlorine) 49Petroleum oil 29 Trixylyl phosphate 13 Tributyl phosphate 9 Epoxidizedlinseed oil (9.5 oxirane oxygen) 0.6 Phenyl didecyl phosphite 0.25

10. The fire-resistant functional fluid of claim 1 in which thetriorganic phosphite is selected from the group consisting of triarylphosphites, trialkyl phosphites and aryl dialkyl phosphites.

11. The fire-resistant functional fluid of claim 1 in which thetriorganic phosphite is selected from the group consisting of triarylphosphites, trialkyl phosphites and phite and trioctyl phosphite.

12. The fire-resistant functional fluid of claim 1 in which the epoxycompound is selected from the group consisting of epoxidized soybeanoil, epoxidized linseed oil, butyl epoxy tallate, butyl epoxy stearateand epoxidized octyl tallate.

References Cited UNITED STATES PATENTS 2,175,877 10/1939 Clark 252--492,245,649 6/1941 Caprio 252-49 2,509,620 5/1950 Watson et al. 252-782,549,270 4/1951 Watson 252-78 2,566,623 9/1951 Moreton 252--782,686,760 8/1954 Watson 252--49.8 X 2,900,342 8/1959 Manteuifel et al.252-57 3,115,465 12/1963 Orlofi et al. 252-498 X 3.136,726 6/1964Moreton 252-78 X DANIEL E. WYMAN, Primary Examiner W. CANNON, AssistantExaminer US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO- 2 W6107 Dated Fehrnary I 'Z J I 7 Inventor(s) D. A. Lima et al It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 4, line 25, "hamful" should read --harmful-.

Column 4, line 72, "epoxized" should read -epoxidized.

Column 5, line 15, "epoxized" should read --epoxidized.

Column 7, line 18-21, should read Claims 7, 8, & 9, line 9, "9.5" shouldread "9.5%".

Column 8, line 19 & 50, "triaryl phosphites, trialkyl phosphides andphite and troctyl phosphite" should read -triphenyl phosphite, phenyldidecyl phosphite and trioctyl phosphite--.

Signed and sealed this hth day of January 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTISCHALK Attestinq Officer ActingCommissioner of Patents FORM PO-IOSO (IQ-G9) USCOMM-DC GUSTO-P69 USIGOVERNMKNY FIINYING OFFICE 19.9 O-J65-J34

